AuraGen Wellness — GLP-1 & GIP Metabolic Response Report

Overview

What This Report Covers

GLP-1 receptor agonists — including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) — are among the most effective metabolic therapies ever developed. But response is highly variable: some individuals lose 25%+ of body weight; others under 5%. A landmark April 2026 genome-wide study of 27,885 patients identified the first robust genetic predictors of both weight loss efficacy and nausea/vomiting risk, including a drug-specific signal in the GIP receptor gene relevant only to tirzepatide users.

This report covers three pharmacogenomic layers: (1) GLP-1 receptor biology — your baseline GLP1R variants and what they predict for semaglutide efficacy and side effects; (2) GIP receptor biology NEW — GIPR variants and tirzepatide-specific response and vomiting risk; and (3) upstream metabolic architecture — TCF7L2, FTO, MC4R, PCSK9, ADRB3, and PPARG variants that shape your overall metabolic phenotype and drug response context.

Semaglutide

Ozempic · Wegovy · Rybelsus

GLP-1 receptor agonist. Activates GLP1R to stimulate glucose-dependent insulin secretion, slow gastric emptying, and suppress appetite via hypothalamic signaling.

GLP1R TCF7L2 ARRB1 FTO

Tirzepatide

Mounjaro · Zepbound

Dual GLP-1 and GIP receptor agonist. Uniquely targets both GLP1R and GIPR, producing superior average weight loss vs. semaglutide but with tirzepatide-specific side effect genetics.

GLP1R GIPR MC4R TCF7L2

Liraglutide

Saxenda · Victoza

First-generation daily GLP-1 receptor agonist. Strong glycemic data; weight loss typically less than semaglutide. GLP1R and ARRB1 variants predict response.

GLP1R ARRB1 TCF7L2

Retatrutide / future agents

GLP-1 / GIP / Glucagon triple agonist

Pipeline: triple agonist. GCG (proglucagon) gene variants may gain relevance as glucagon receptor co-agonism becomes clinical. Monitoring status.

GLP1R GIPR GCG

Gene Panel · Layer 1

GLP1R — GLP-1 Receptor

The GLP1R gene encodes the receptor that all GLP-1 drugs directly target. Variants here are the most clinically direct pharmacogenomic signal in this report — they alter receptor structure, signaling efficiency, and downstream metabolic effects.

GLP1R Glucagon-Like Peptide-1 Receptor · Chr 6p21.1

Key Variants

rs10305420 (Ala316Thr) · rs6923761 (Gly168Ser) · rs2268641

Evidence Level

High — Nature 2026 GWAS N=27,885

rs10305420 Effect

Missense variant. Effect allele associated with −0.76 kg incremental weight loss per copy on GLP-1 medications. Also associated with increased nausea/vomiting risk (P = 2.9 × 10⁻¹⁰).

rs6923761 (Gly168Ser) Effect

AA carriers associated with excess weight and higher fasting glucose. GC carriers show lower obesity prevalence. Alters receptor coupling efficiency. Affects ARRB1-mediated internalization.

Clinical Interpretation

GLP1R variants are the most direct predictor of drug-target pharmacogenomics for semaglutide and tirzepatide. The rs10305420 effect allele appears to confer both incremental efficacy and slightly elevated nausea risk — a potential explanation for the observed correlation between nausea and weight loss in GLP-1 trials. Effect size per allele copy is modest (~0.76 kg) but directionally meaningful at a population level and relevant for individualized expectations-setting.

ARRB1 Beta-Arrestin-1 · Chr 11q13.2 · Downstream GLP1R signaling

Key Variants

rs140226575 · Thr370Met

Evidence Level

High — Lancet Diab Endocrinol 2023, N=4,571

Mechanism & Clinical Significance

Beta-arrestin-1 mediates GLP1R internalization and downstream biased signaling. Carriers of ARRB1 risk variants show significantly reduced glycemic response to GLP-1 receptor agonists (HbA1c reduction attenuated). The 2023 Lancet DIRECT consortium pharmacogenomic study identified ARRB1 as the top signal in a GWAS of 4,571 patients, with clinical recommendation that ARRB1 variant carriers may benefit from earlier initiation of GLP-1 therapy to compensate for reduced receptor signaling efficiency.

Gene Panel · Layer 2 NEW — April 2026

GIPR — GIP Receptor & Tirzepatide Response

The glucose-dependent insulinotropic polypeptide receptor (GIPR) is the second target of tirzepatide — the drug mechanism that makes it distinct from all prior GLP-1 monotherapies. A landmark April 2026 Nature study identified the first GIPR pharmacogenomic signal: a variant that dramatically amplifies vomiting risk specifically in tirzepatide users, with no significant signal in semaglutide-only users.

Why this matters for your drug choice: GIP receptor co-agonism is generally believed to act as a "buffer" against the nausea caused by GLP-1 receptor activation. The rs1800437 variant in GIPR may reduce or abolish this buffering effect — meaning that for carriers, tirzepatide's tolerability advantage over semaglutide may be substantially diminished or reversed. This is the first evidence that drug selection between these two agents can be genetically informed.

GIPR Glucose-Dependent Insulinotropic Polypeptide Receptor · Chr 19q13.3

Key Variant

rs1800437 (Glu354Gln)

Evidence Level

High — Nature 2026, N=27,885

Drug Specificity

Tirzepatide only. No significant association detected in semaglutide-treated patients in the same cohort. This variant is the first genetically tirzepatide-specific pharmacogenomic signal documented in the literature.

Effect Magnitude

Carriers of rs1800437 risk allele: significantly elevated vomiting risk on tirzepatide. Individuals homozygous for both rs1800437 (GIPR) and rs10305420 (GLP1R) risk alleles: estimated 15× higher vomiting odds on tirzepatide vs. double non-carriers.

Proposed Mechanism

GIPR co-activation on tirzepatide is hypothesized to dampen GLP-1-induced nausea via GIP receptor signaling in the brainstem. The Glu354Gln substitution may alter receptor coupling efficiency or reduce GIP-mediated suppression of area postrema activation, removing the tolerability buffer. This aligns with clinical observations that tirzepatide typically causes less nausea than semaglutide — an effect that may be genotype-dependent.

Combined GLP1R × GIPR Genotype Risk Matrix

Based on 23andMe / Nature 2026 data (N=27,885). All estimates relative to double-reference genotype on tirzepatide.

GLP1R rs10305420	GIPR rs1800437	Drug	Vomiting Risk	Weight Loss Prediction
Ref/Ref	Ref/Ref	Tirzepatide	Reference (baseline)	Average expected response
Effect/Ref	Ref/Ref	Semaglutide	Moderately elevated	+0.76 kg additional loss (per allele)
Ref/Ref	Risk/Ref	Tirzepatide	Elevated — GIPR buffer reduced	No weight loss impact detected
Effect/Effect	Risk/Risk	Tirzepatide	~15× above baseline	Incremental weight loss offset by tolerability challenges
Effect/Ref	Ref/Ref	Tirzepatide	Moderately elevated (GLP1R signal)	Enhanced efficacy expected; monitor GI tolerance

Gene Panel · Layer 3

Upstream Metabolic Architecture

Beyond the direct drug-target genes, your broader metabolic genotype shapes the terrain in which GLP-1 and GIP receptor agonists operate — influencing baseline appetite regulation, fat mass set-point, insulin secretion capacity, and cardiovascular risk. These variants contextualize your overall metabolic phenotype.

Gene	rsID	Function	Metabolic Relevance	GLP-1 Interaction	Evidence
TCF7L2	rs7903146	Transcription factor, β-cell function, incretin sensitivity	Strongest common T2D risk gene. Risk T allele reduces incretin-stimulated insulin secretion by ~30%.	Risk allele carriers show attenuated glycemic response to GLP-1RAs in multiple RCTs. Affects insulinotropic but not necessarily weight loss arm.	High · PMID 28878247
FTO	rs9939609	Fat mass & obesity-associated, appetite/hypothalamic	Risk A allele: +0.39 kg/m² BMI per allele, reduced satiety signaling. Affects food intake circuits overlapping with GLP-1 central mechanisms.	FTO risk variants associated with increased food intake and reduced satiety — the same pathways modulated by GLP-1's central actions. May require higher effective doses.	High · PMID 17554300
MC4R	Multiple rare variants	Melanocortin 4 receptor — most common monogenic obesity gene	Pathogenic MC4R variants: most common genetic obesity cause (~1.4% of severe obesity). Historically, MC4R-deficient patients were thought to be drug-resistant.	Tirzepatide effective even in MC4R mutation carriers — SURMOUNT-1 data (N=32 MC4R carriers) showed comparable 18.3% weight loss vs. 19.9% non-carriers. This is clinically important: MC4R status does not contra-indicate GLP-1/GIP therapy.	High · Nature Med 2025
PCSK9	rs11591147	Proprotein convertase — LDL receptor degradation	Loss-of-function variant (R46L): ~50% LDL reduction, strong cardiovascular protection. Gain-of-function: elevated LDL, familial hypercholesterolemia risk.	Indirect relevance: GLP-1 medications have cardiovascular benefits (SELECT trial). PCSK9 variants contextualize cardiovascular risk profile that GLP-1 therapy partially addresses.	High · PMID 26631059
ADRB3	rs4994	β3-adrenergic receptor — adipose tissue thermogenesis	Trp64Arg variant: reduced resting metabolic rate, impaired lipolysis in visceral fat, higher obesity risk in carriers. Associated with impaired weight loss on caloric restriction.	ADRB3 Arg64 carriers may have blunted thermogenic response. GLP-1 drugs act partly through enhanced energy expenditure — this variant may modulate that arm of the mechanism.	Moderate · PMID 7671580
PPARG	rs1801282	Peroxisome proliferator-activated receptor γ — adipogenesis, insulin sensitivity	Pro12Ala: minor Ala allele protective — improved insulin sensitivity, ~20% reduced T2D risk. Modulates adipocyte differentiation and fat distribution.	PPARG Pro12Ala interacts with dietary fat composition and metabolic drug efficacy. Ala allele carriers may have better baseline insulin sensitivity context for GLP-1 therapy.	Moderate · PMID 9614458
GCG	Regulatory variants	Proglucagon gene — encodes GLP-1, GLP-2, glucagon, oxyntomodulin	GCG encodes the precursor that is post-translationally cleaved into GLP-1 and GLP-2, among other peptides. Variants in GCG regulatory regions may affect baseline GLP-1 secretion.	Relevant as triple agonists (retatrutide) entering Phase 3 include glucagon receptor co-activation. GCG variants will be added to this report as pipeline agents advance to clinical use.	Monitoring · Pipeline relevance

Note on GLP-2 (GLP2R): GLP-2, also encoded by the GCG gene, acts on a separate receptor (GLP2R) and governs intestinal growth and mucosal repair rather than metabolism or satiety. GLP-2 analogs (teduglutide) are approved for short bowel syndrome only. No consumer-actionable pharmacogenomic variants exist for GLP2R at this time — the first human GLP2R loss-of-function case was only documented in 2024. AuraGen will add GLP2R content if evidence reaches consumer-actionable threshold.

Interpretation Guide

Translating Your Results to Clinical Context

The following framework helps translate your individual genotype profile into questions to discuss with your prescriber. This is not a prescription recommendation — it is a structured starting point for a precision pharmacology conversation.

Questions your genotype may help answer

GLP1R rs10305420 — Effect allele carrier: You may have somewhat enhanced weight loss response to GLP-1 medications, but also elevated nausea risk. Discuss a slower titration schedule with your physician and consider whether the marginal efficacy benefit warrants antiemetic co-therapy if tolerability becomes limiting.
GIPR rs1800437 — Risk allele carrier on tirzepatide: Your GIP receptor buffering of GLP-1-induced nausea may be reduced or absent. If you are choosing between semaglutide and tirzepatide, this finding suggests tirzepatide may not offer its typical tolerability advantage for you. Discuss with your physician whether semaglutide monotherapy — without the GIPR component — may be equally effective with better GI tolerability.
Double risk genotype (GLP1R effect + GIPR risk): You carry both the GLP1R signal associated with elevated nausea and the GIPR signal that removes the tirzepatide tolerability buffer. Estimated 15× elevated vomiting odds on tirzepatide. Strongly consider semaglutide as first-line option, and discuss a very conservative titration protocol.
TCF7L2 rs7903146 — Risk T allele: Your insulin secretion response to GLP-1 stimulation may be attenuated. This does not eliminate GLP-1 benefit — the weight loss and cardiovascular arms are not TCF7L2-dependent — but glycemic response metrics may be less dramatic than average.
MC4R pathogenic variant carrier: Historically, MC4R deficiency was considered a potential barrier to GLP-1 response. SURMOUNT-1 data now shows tirzepatide works comparably in MC4R mutation carriers. This is not a contraindication for GLP-1/GIP therapy.
FTO rs9939609 — Risk AA genotype: Your central appetite regulation may be more strongly influenced by food reward circuits. GLP-1's hypothalamic satiety mechanism is particularly relevant here. Some evidence suggests FTO risk carriers benefit substantially from the central appetite suppression component of GLP-1 therapy, which may partially offset impaired satiety signaling.

Full Data Table

All Assessed Variants

Gene	rsID / Variant	Chr Position (hg38)	Risk Allele	Population Freq.	Effect	Primary Citation
GLP1R	rs10305420	6:39,014,832	T (Ala316Thr)	~15–20% EUR	↑ Weight loss efficacy; ↑ nausea/vomiting on GLP-1 medications	Auton et al., Nature 2026
GLP1R	rs6923761	6:39,016,555	A (Gly168Ser)	~30% EUR	AA: ↑ obesity risk, ↑ fasting glucose; alters receptor coupling	Michałowska et al., Front Endocrinol 2022
GLP1R	rs2268641	6:39,021,104	T	~35% EUR	TT: lower obesity frequency in Polish cohort; downstream signaling modulation	Michałowska et al., Front Endocrinol 2022
GIPR	rs1800437	19:45,892,628	C (Glu354Gln)	~38% EUR	↑↑ Vomiting risk on tirzepatide; no signal on semaglutide; reduces GIP buffer effect	Auton et al., Nature 2026 NEW
ARRB1	rs140226575	11:74,896,241	A	~5% EUR	↓ GLP1R internalization efficiency; ↓ glycemic response to GLP-1RAs	Dawed et al., Lancet Diab Endocrinol 2023
ARRB1	Thr370Met	11:74,898,103	T	Rare	Biased GLP1R signaling; altered beta-arrestin recruitment, attenuated HbA1c reduction	Dawed et al., Lancet Diab Endocrinol 2023
TCF7L2	rs7903146	10:112,998,590	T	~30% EUR	↓ Incretin-stimulated insulin secretion ~30%; ↑ T2D risk; attenuated HbA1c response to GLP-1RAs	Pearson et al., Diabetologia 2017 · PMID 28878247
FTO	rs9939609	16:53,820,527	A	~45% EUR	+0.39 kg/m² BMI per allele; ↓ satiety signaling; ↑ food intake reward-driven behavior	Frayling et al., Science 2007 · PMID 17554300
FTO	rs1558902	16:53,803,574	A	~42% EUR	+0.39 kg/m² BMI per risk allele; correlated with reduced satiety hormone response	Locke et al., Nature 2015 · PMID 25673413
MC4R	Multiple pathogenic	18:57,851,099	Various LoF	~1.4% severe obesity	Most common monogenic obesity cause; tirzepatide effective in carriers (SURMOUNT-1)	Loos et al., Nature Med 2025 · PMID 38740993
PCSK9	rs11591147	1:55,505,647	T (R46L LoF)	~2% EUR	LoF: ~50% LDL reduction, strong CV protection; GoF: familial hypercholesterolemia risk	Cohen et al., NEJM 2006 · PMID 26631059
ADRB3	rs4994 (Trp64Arg)	8:37,660,354	C (Arg64)	~10% EUR; ~30% Asian	↓ Resting metabolic rate; ↓ lipolysis in visceral adipose; ↓ thermogenic response	Walston et al., NEJM 1995 · PMID 7671580
PPARG	rs1801282 (Pro12Ala)	3:12,351,626	G (Pro12)	~75% EUR carry Pro/Pro	Ala allele: ↑ insulin sensitivity, ~20% ↓ T2D risk; Pro/Pro: slightly ↓ insulin sensitivity	Altshuler et al., Nature Genet 2000 · PMID 9614458
GCG	Regulatory	2q24.2	–	–	Encodes GLP-1, GLP-2, glucagon precursor. Monitoring for triple agonist pipeline relevance.	Monitoring status

References

Supporting Literature

Nature 2026 Auton A et al. "Genetic predictors of GLP1 receptor agonist weight loss and side effects." Nature. April 8, 2026. N=27,885. GLP1R rs10305420 weight loss GWAS; GIPR rs1800437 tirzepatide-specific nausea signal.

PMID 36690612 Dawed AY et al. "Pharmacogenomics of GLP-1 Receptor Agonists: A Genome-Wide Analysis of Observational Data and Large Randomised Controlled Trials." Lancet Diabetes & Endocrinology. 2023. N=4,571. ARRB1 top signal; DIRECT consortium.

PMID 35864097 Michałowska J et al. "Association of GLP1R variants rs2268641 and rs6923761 with obesity and other metabolic parameters in a Polish cohort." Front Endocrinol. 2022.

PMID 28878247 Pearson ER et al. "TCF7L2 genotype and response to GLP-1 receptor agonists in type 2 diabetes." Diabetologia. 2017. TCF7L2 rs7903146 attenuates GLP-1-stimulated insulin secretion.

PMID 17554300 Frayling TM et al. "A common variant in the FTO gene is associated with body mass index." Science. 2007. FTO rs9939609 obesity association landmark study.

Nature Med 2025 Loos RJF et al. "Tirzepatide leads to weight reduction in people with obesity due to MC4R deficiency." SURMOUNT-1 MC4R sub-analysis. 18.3% vs. 19.9% weight loss: comparable efficacy.

PMID 26631059 Cohen JC et al. "PCSK9 R46L loss-of-function and cardiovascular outcomes." NEJM. 2006. rs11591147 LDL reduction and CV protection data.

PMID 7671580 Walston J et al. "Time of onset of non-insulin-dependent diabetes mellitus and ADRB3 Trp64Arg." NEJM. 1995. Founding ADRB3 thermogenesis variant paper.

PMID 9614458 Altshuler D et al. "The common PPARgamma Pro12Ala polymorphism is associated with decreased risk of type 2 diabetes." Nature Genet. 2000.

PMID 39340476 Jaramishian R et al. "Novel homozygous nonsense mutation in glucagon-like peptide-2 receptor gene resulting in severe human illness." JPGN Reports. 2024. First documented GLP2R-deficient human phenotype — basis for excluding GLP-2 from consumer panels.