Ingredient Safety Guide
Research-backed ratings for ingredients in grooming products and supplements. Each page covers testosterone impact, regulatory status, and what to look for on labels.
01PhthalatesAvoid — multiple human studies link phthalate exposure to reduced testosterone, sperm quality decline, and anogenital distance changes; EU classifies several as reprotoxic Category 1B.Poor02Diethyl Phthalate (DEP)Avoid — the most common phthalate in men's fragranced products and a confirmed anti-androgen in animal models.Poor03PropylparabenAvoid — more estrogenic than methylparaben and restricted in EU cosmetics due to endocrine concerns.Poor04ButylparabenAvoid — the most potent estrogenic paraben; rodent studies show reduced sperm count and testosterone.Poor05BPA (Bisphenol A)Avoid — well-documented endocrine disruptor associated with lower testosterone and sperm quality in human studies.Poor06BPS (Bisphenol S)Avoid — the 'BPA-free' replacement with similar endocrine activity; not the upgrade marketing implies.Poor07TriclosanAvoid — FDA banned it from consumer soaps in 2016 over endocrine and antimicrobial-resistance concerns; thyroid disruption is well documented.Poor08TriclocarbanAvoid — banned by FDA in OTC soaps in 2016; amplifies androgen signaling abnormally and is environmentally persistent.Poor09Oxybenzone (Benzophenone-3)Avoid — absorbed into bloodstream above FDA toxicology thresholds and shows estrogenic activity; banned in Hawaii sunscreens.Poor10Octinoxate (Ethylhexyl Methoxycinnamate)Avoid — estrogenic in animal models and absorbed systemically; safer mineral alternatives exist.Poor11HomosalateAvoid — EU restricted concentration in 2021 citing endocrine concerns; FDA categorized as not GRASE pending more safety data.Poor12OctocryleneAvoid — degrades into benzophenone over time, raising both endocrine and carcinogenicity concerns.Poor13DMDM HydantoinAvoid — slowly releases formaldehyde, a known carcinogen; shouldn't be reapplied to the scalp daily.Poor14Quaternium-15Avoid — formaldehyde-releasing preservative banned in EU cosmetics since 2023; one of the highest-potency formaldehyde releasers in personal care.Poor15PFAS (Per- and Polyfluoroalkyl Substances)Avoid — strongly linked in human cohorts to lower testosterone and sperm count; bioaccumulate and persist in the body for years.Poor16Cocamide DEAAvoid — IARC classifies cocamide DEA as a possible human carcinogen (Group 2B); banned in California Prop 65 listings.Poor17TolueneAvoid — known reproductive toxicant; restricted in EU cosmetics and listed under California Prop 65.Poor18Cyclic Siloxanes (D4/D5)Avoid — EU classifies D4 as a reproductive toxicant and restricts both D4 and D5 in rinse-off cosmetics.Poor19MethylparabenUse caution — weakly estrogenic and detectable in nearly all men's grooming products, contributing to cumulative xenoestrogen load.Mediocre20Aluminum ChlorohydrateUse caution — high consumer concern but evidence for direct testosterone or cancer effects is weak; aluminum-free alternatives are widely available.Mediocre21Sodium Lauryl Sulfate (SLS)Mostly fine but irritating — not a hormone disruptor or carcinogen; the main concern is skin and scalp irritation with daily use.Mediocre22Sodium Laureth Sulfate (SLES)Acceptable — the product itself is mild; the real concern is 1,4-dioxane contamination from manufacturing, which is regulated in NY and CA.Mediocre23Aluminum (in Deodorant)Use caution — no strong link to cancer or testosterone; aluminum-free deodorants are an easy switch if you're concerned.Mediocre24FluorideProbably fine at toothpaste and water concentrations — chronic high-dose exposure is a concern worth tracking, but typical dental use is not.Mediocre25SucraloseProbably fine occasionally — the gut microbiome data is concerning enough to avoid daily use, especially in pre-workout taken on an empty stomach.Mediocre26AspartameLimit but don't panic — IARC moved it to 'possibly carcinogenic' in 2023, though FDA's acceptable daily intake remains generous.Mediocre27Soy Protein IsolateProbably fine in moderation — meta-analyses don't show meaningful testosterone or sperm effects at normal intakes; whey or pea protein avoids the question entirely.Mediocre28Lavender OilUse sparingly — case reports of gynecomastia in boys exposed to lavender products; daily topical use is the avoidable form.Mediocre29Tea Tree OilUse sparingly — same case-series concern as lavender; fine occasionally for spot acne use, less ideal as a daily-use shampoo ingredient.Mediocre30Petrolatum (Mineral Oil)Acceptable from reputable brands — cosmetic-grade petrolatum is well-refined; the 'petroleum byproduct' framing online overstates the real risk.Mediocre31FenugreekMixed evidence — modest libido benefits in some studies, but the testosterone story is inconsistent and may include 5α-reductase inhibition.Mediocre32D-Aspartic Acid (DAA)Largely overhyped — initial testosterone-boosting studies didn't replicate in trained men, and high doses may backfire.Mediocre33AshwagandhaSolid choice — one of the few 'T-booster' ingredients with consistent RCT support for modest testosterone and recovery benefits.Good34Tongkat AliPromising for men with stress-related low T — only buy from brands with third-party assays; the supplement market is full of underdosed and adulterated tongkat.Good35ZincTake if deficient — well-established role in testosterone and sperm production; megadosing won't push T above normal in already-replete men.Good36MagnesiumWorth taking — modest free-testosterone benefit and clear effects on sleep quality, where most men are under-supplied.Good37BoronCheap and worth trying — small but consistent free testosterone effect via SHBG reduction; well-tolerated at 6–10 mg/day.Good38Vitamin D3 (Cholecalciferol)Take it if you're deficient — one of the most replicable links between a vitamin and testosterone; check serum 25(OH)D first.Excellent
38 ingredients reviewed · Updated regularly from peer-reviewed research