Sport research · Bodybuilding

Peptides for bodybuilding: body composition, by the evidence

Bodybuilding is the one sport judged entirely on body composition, so it is the one sport page where the Fat Loss and Muscle axes carry real weight. Here is what the published research supports — and what it does not.

Low-contact sportWADA 2026 status checkedVerified PubMed citations

Tested athletes: read this first

Under the WADA 2026 Prohibited List (in force from 1 January 2026), BPC-157 is named under S0, TB-500 under S2.3, Ipamorelin and Tesamorelin under S2.2.4 and MOTS-c under S4.4.1 — all prohibited in and out of competition. Research peptides with no regulatory approval anywhere are caught by S0’s catch-all wording. Tested athletes: these are banned. South African athletes can check with SAIDS and the official 2026 List.

The demands

What bodybuilding asks of the body

A bodybuilding year splits into an off-season (building muscle through progressive overload and a calorie surplus) and a contest prep (losing fat while keeping as much muscle as possible, usually over 12–20 weeks). Both halves are body-composition problems, which is why this page — unlike the combat-sport pages — weights Fat Loss & Metabolism on the radar.

A crucial honesty point: the catalogue’s Muscle scores are modest across the board. The GH-axis compounds have human pharmacology but no trial showing muscle gain in trained lifters, and the GLP-1 class shows mostly fat-mass loss with lean mass preserved proportionally, not built. The largest evidence scores in the whole catalogue are for weight loss in people with obesity — a different population from a contest-prep athlete.

South Africa has an active federated scene (IFBB and natural federations) and a large recreational gym culture. Natural federations test to the WADA List; others do not test at all. This page lists the WADA status of everything, because "untested federation" is a choice an athlete should make knowingly.

Mapped to the evidence radar

Each demand below is mapped to one of the ten fixed research areas on our evidence radar. The heavier the weight, the more that area counts when compounds are ranked for Bodybuilding: Muscle & Body Composition ×3, Fat Loss & Metabolism ×2, Recovery & Repair ×2, Sleep & Recovery Rhythm ×2, Skin, Hair & Glow ×1.

Building and keeping muscle · Muscle & Body Composition
Tesamorelin trials report modest lean-mass gains alongside visceral-fat loss in HIV lipodystrophy; Ipamorelin produces clean GH pulses in human pharmacology. Both are named under S2.2.4.
Contest-prep fat loss · Fat Loss & Metabolism
The GLP-1 research compounds have the strongest human data in the catalogue — in obesity trials, not trained athletes. DXA sub-studies show the loss is mostly fat mass.
Training-induced tendon load · Recovery & Repair
Heavy pressing and pulling stress elbows and shoulders. Repair research is preclinical.
Sleep in a deficit · Sleep & Recovery Rhythm
Late contest prep often disrupts sleep. Sleep evidence here includes Tesamorelin’s GHRH sleep-lab work and Russian pineal-peptide research.

By the evidence

Highest-scoring compounds for Bodybuilding

Ranked by weighted evidence score across Bodybuilding’s research areas. A reading aid for the literature — not a recommendation, and not a performance claim.

Top three for Bodybuilding, overlaid · strength of published evidence per area

Show the scores as a table

Evidence score per research area, 0 to 10
Area	Tesamorelin	Ipamorelin	MOTS-c
Fat Loss & Metabolism	8	5	8
Appetite Control	3	3	2
Muscle & Body Composition	7	8	7
Recovery & Repair	6	7	6
Skin, Hair & Glow	5	5	3
Gut & Immune	4	5	4
Cognition & Focus	7	4	4
Mood & Calm	5	4	4
Sleep & Recovery Rhythm	7	7	4
Longevity & Energy	7	6	9

Tesamorelin

Restocking

6.8Bodybuilding match

Muscle & Body CompositionPrimary7/10

Clinically documented to increase functional lean body mass alongside visceral fat reduction.

Fat Loss & Metabolism8/10

FDA-approved Phase 3 trial proven ~15-18% reduction in deep pathogenic visceral adipose tissue.

Recovery & Repair6/10

Raises IGF-1, the axis studied for collagen synthesis and connective-tissue repair.

S2.2.4Tesamorelin is named as a GHRH analogue (S2.2.4), non-Specified, prohibited at all times — even though it is an approved medicine elsewhere. Tested athletes: this is banned.

Research overview Notify me on restock Glossary

Ipamorelin

Restocking

6.7Bodybuilding match

Muscle & Body CompositionPrimary8/10

Selectively stimulates potent, pulsatile growth hormone and IGF-1 release without elevating cortisol.

Fat Loss & Metabolism5/10

Elevated GH levels promote lipolysis and preferential mobilization of stored triglycerides.

Recovery & Repair7/10

Enhanced IGF-1 upregulates collagen synthesis and accelerates connective tissue reconstruction.

S2.2.4Ipamorelin is named among the growth hormone secretagogues (S2.2.4), non-Specified, prohibited at all times. Tested athletes: this is banned.

Research overview Notify me on restock Glossary

MOTS-c

Restocking

6.0Bodybuilding match

Muscle & Body CompositionPrimary7/10

Enhances skeletal muscle glucose uptake and dramatically increases physical exercise capacity.

Fat Loss & Metabolism8/10

Activates AMPK to stimulate robust fatty acid oxidation and reverse diet-induced insulin resistance.

Recovery & Repair6/10

Stimulates mitochondrial biogenesis, accelerating cellular metabolic recovery post-exertion.

S4.4.1MOTS-c is named among the AMPK-activating metabolic modulators (S4.4.1), non-Specified, prohibited at all times. Tested athletes: this is banned.

Research overview Notify me on restock Glossary

KLOW

In stock

5.8Bodybuilding match

Muscle & Body CompositionPrimary6/10

Promotes myoblast proliferation and accelerates functional recovery after mechanical muscle tears.

Fat Loss & Metabolism2/10

Little or no published research links this compound to this area.

Recovery & Repair10/10

Extensive animal and tissue studies demonstrate rapid healing of tendon, ligament, muscle, and bone.

S0 + S2.3KLOW contains BPC-157 (named in S0) and TB-500 (named in S2.3). Tested athletes: this is banned.

Research overview View compound

TB-500

Restocking

5.0Bodybuilding match

Muscle & Body CompositionPrimary5/10

Upregulates contractile protein repair and accelerates myofiber regeneration post-trauma.

Fat Loss & Metabolism2/10

Little or no published research links this compound to this area.

Recovery & Repair9/10

Master actin-sequestering protein fragment driving rapid cell migration to sites of muscle/cardiac injury.

S2.3The List names "Thymosin-β4 and its derivatives e.g. TB-500" under growth factors (S2.3), non-Specified, prohibited at all times. Tested athletes: this is banned.

Research overview Notify me on restock Glossary

NAD+

Restocking

5.0Bodybuilding match

Muscle & Body CompositionPrimary5/10

Optimizes muscle mitochondrial ATP synthesis and cellular energy throughput.

Fat Loss & Metabolism4/10

Precursor trials explore insulin sensitivity and metabolic endpoints, with mixed results.

Recovery & Repair6/10

Accelerates cellular repair following metabolic or oxidative stressors.

M2.2NAD+ itself is not named. Delivering anything by IV infusion or injection above 100 mL per 12 hours outside hospital care is a prohibited method (M2.2).

Research overview Notify me on restock Glossary

Scores (0–10) rate the strength of the published research link in each area — large human trials score highest, then smaller human studies (Russian clinical research counted at full weight), then animal and lab work. They describe the literature, not an outcome for any person or athlete. All compounds are supplied strictly for laboratory research purposes and are not for human consumption.

The literature

What published research says about bodybuilding

Tesamorelin: pooled phase 3 trials in HIV-associated abdominal fat reported visceral-fat reduction — the largest human dataset among the GH-axis compounds.[1]
SURMOUNT-1: Tirzepatide produced 15.0–20.9% mean weight reduction at 72 weeks in adults with obesity.[2]
Retatrutide phase 2: −24.2% mean body weight at 48 weeks on the 12 mg dose in adults with obesity.[3]

Anti-doping

WADA 2026 status of every compound on this page

Quoted from the WADA Prohibited List 2026 (in force 1 January 2026). Where a compound is not named, we say so and explain how the List’s wording applies.

WADA 2026 Prohibited List status per compound
Compound	Status	What the 2026 List says
Tesamorelin	Prohibited — named · S2.2.4	Tesamorelin is named as a GHRH analogue (S2.2.4), non-Specified, prohibited at all times — even though it is an approved medicine elsewhere. Tested athletes: this is banned.
Ipamorelin	Prohibited — named · S2.2.4	Ipamorelin is named among the growth hormone secretagogues (S2.2.4), non-Specified, prohibited at all times. Tested athletes: this is banned.
MOTS-c	Prohibited — named · S4.4.1	MOTS-c is named among the AMPK-activating metabolic modulators (S4.4.1), non-Specified, prohibited at all times. Tested athletes: this is banned.
KLOW	Prohibited — named · S0 + S2.3	KLOW contains BPC-157 (named in S0) and TB-500 (named in S2.3). Tested athletes: this is banned.
TB-500	Prohibited — named · S2.3	The List names "Thymosin-β4 and its derivatives e.g. TB-500" under growth factors (S2.3), non-Specified, prohibited at all times. Tested athletes: this is banned.
NAD+	Method limit (IV) · M2.2	NAD+ itself is not named. Delivering anything by IV infusion or injection above 100 mL per 12 hours outside hospital care is a prohibited method (M2.2).

FAQ

Bodybuilding: common questions

Which peptides are banned for natural bodybuilders?

Natural federations test to the WADA List. Named on the 2026 List: BPC-157 (S0), TB-500 (S2.3), Ipamorelin, CJC-1295, sermorelin and Tesamorelin (S2.2.4), MOTS-c (S4.4.1). Retatrutide is unapproved and falls under S0’s wording. Tirzepatide is not listed.

Do GLP-1 peptides cause muscle loss?

In the obesity trials, DXA sub-studies show most weight lost is fat mass, with lean mass falling roughly in proportion — preserved relative to fat, not built. That is why the Muscle score for these compounds is low.

Is there a bodybuilding goal hub too?

Yes — the bodybuilding and lean-muscle hubs cover the catalogue from a shopping angle; this page is the evidence-and-rules view.

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