Happy Mammoth is an Australian-founded supplement brand that sells products made from generally recognized herbal ingredients, but several red flags raise legitimate questions about its safety and transparency. The company has faced a Proposition 65 violation notice in California for heavy metals in two products, has over 200 complaints on the Better Business Bureau, and does not publish the specific dosages of ingredients in its flagship product. None of this means the supplements are definitively dangerous, but it does mean you should weigh the evidence carefully.
What’s in the Products
Happy Mammoth’s best-known supplement, Hormone Harmony, contains 12 active ingredients: maca root extract, broccoli sprout, chaste tree berry extract, ashwagandha root extract, wild yam extract, fennel seed powder extract, berberine, gymnema extract, rosemary extract, chamomile extract, vitamin B6, and rhodiola rosea extract. The capsules also contain hypromellose (a plant-based capsule shell), Nu-MAG, and Nu-Flow as inactive ingredients.
Individually, most of these are well-studied herbal extracts with reasonable safety profiles when taken at appropriate doses by healthy adults. Ashwagandha, for instance, has been tested in clinical trials at doses ranging from 240 mg to 1,000 mg per day and shown to reduce cortisol and ease stress symptoms. Maca root, rhodiola, and chaste tree berry all have published research supporting their traditional uses.
The problem is that Happy Mammoth claims all ingredients are “dosed at clinically-proven amounts” but does not actually list the milligram amounts for any of them. Without that information, there’s no way to verify whether you’re getting an effective dose, an underdosed token amount, or a dose high enough to cause interactions. This is a significant transparency gap, especially for a product marketed to people dealing with hormonal symptoms.
The Heavy Metals Issue
In 2024, California’s Attorney General’s office issued a Proposition 65 violation notice to Happy Koala LLC (the company doing business as Happy Mammoth). The notice identified two specific products with chemicals exceeding California’s allowable levels: NewSlim Complete Protein Meal Vanilla Bean was flagged for lead and mercury, and FitSlim SuperGreens Vanilla Bean was flagged for lead.
Proposition 65 thresholds are stricter than federal limits, so exceeding them doesn’t necessarily mean a product poses immediate danger. But lead and mercury are cumulative toxins, meaning they build up in your body over time. For a product you’re meant to take daily, even small amounts above safe thresholds matter. This notice also raises questions about the company’s quality control and testing processes, which Happy Mammoth does not publicly detail.
Regulatory Status in Australia
Happy Mammoth is based in Australia, where dietary supplements (called “listed medicines”) are regulated by the Therapeutic Goods Administration (TGA). One of its products, Hormone Harmony Plus, was listed on Australia’s Register of Therapeutic Goods but was cancelled by the TGA under Section 30(1)(c) of the Therapeutic Goods Act, with an effective date of March 27, 2026. This section of the law covers cancellations initiated when a product no longer meets listing requirements.
In the United States, supplements do not require FDA approval before being sold. They fall under a category where manufacturers are responsible for ensuring their own products are safe. The FDA only steps in after problems are reported. This means Happy Mammoth’s U.S. products have not been independently verified for safety or efficacy by any government agency.
Consumer Complaints
The Better Business Bureau lists 215 complaints against Happy Mammoth LLC, based in Miami, Florida. While the BBB profile doesn’t break down every complaint by category, consumer reviews mention digestive issues. One customer reported nausea and stomach pain after two weeks of taking the Ultimate GLP-1 product. No formal product recalls have been issued.
Some digestive discomfort is common with herbal supplements, particularly ones containing berberine or gymnema, which can affect blood sugar and gut function. But a high complaint volume relative to a brand’s size is worth noting, especially when combined with other transparency concerns.
Ingredient Interactions to Watch For
Several ingredients in Hormone Harmony have the potential to interact with medications or affect specific health conditions. Berberine lowers blood sugar and can amplify the effects of diabetes medications. Chaste tree berry influences hormone levels, particularly prolactin and progesterone, and can interfere with hormonal birth control or fertility treatments. Ashwagandha may affect thyroid hormone levels, which is relevant if you’re on thyroid medication.
Wild yam and fennel both have mild estrogenic properties, meaning they mimic estrogen in the body to some degree. For people with estrogen-sensitive conditions like certain breast cancers, endometriosis, or uterine fibroids, this is a real concern. Rhodiola can interact with antidepressants and blood pressure medications.
Stacking 12 active herbal extracts in a single capsule increases the chance of interactions, both with each other and with anything else you’re taking. The fact that the doses aren’t disclosed makes it harder to assess your actual risk.
Who Should Be Extra Cautious
Pregnant and breastfeeding women should avoid Happy Mammoth supplements. Several of the ingredients in Hormone Harmony, including chaste tree berry, ashwagandha, and berberine, lack sufficient safety data in pregnancy or are actively contraindicated. The company’s website does not appear to provide prominent warnings for these populations.
People taking prescription medications for diabetes, thyroid conditions, depression, high blood pressure, or hormone-related conditions should be particularly careful given the interaction potential described above. The same goes for anyone scheduled for surgery, since several of these herbs can affect blood clotting or blood pressure.
The Bottom Line on Safety
Happy Mammoth uses real herbal ingredients that have legitimate research behind them individually. The products are not inherently dangerous for most healthy adults. But the company falls short on transparency in ways that matter: no published dosages, no publicly available third-party testing results, a Proposition 65 violation for heavy metals in two products, a TGA cancellation in Australia, and a high volume of consumer complaints. These aren’t dealbreakers on their own, but together they paint a picture of a brand that asks for more trust than it earns through verification. If you decide to try their products, choosing a brand that publishes full dosage information and independent testing certificates would give you a clearer picture of what you’re actually putting in your body.