Scientific References

1. Susan Mayor, “Erection Hardness Scale Proves Effective In Assessing Erection Quality”, 28 Mar 2008,

2. Cohen AJ., Bartlik B., “Ginkgo biloba for antidepressant-induced sexual dysfunction” 1998 Apr-Jun

3. UroToday, Volume 3 2010, “Safety and Efficacy of the Herbal Drug Hypericum Perforatum for the Treatment of Premature Ejaculation”,

4. Chemistry of amino acids and protein structure. (n.d.)

5. Ciacci, C., Franceschi, F., Purchiaroni, F., Capone, P., Buccelletti, F., Iacomini, P., ... Gasbarrini, G. (2011). "Effect of beta-glucan, inositol and digestive enzymes in GI symptoms of patients with IBS." European Review for Medical and Pharmacological Sciences, 15(6), 637–643

6. Rao, R., & Samak, G., 2012, January, “Role of glutamine in protection of intestinal epithelial tight junctions.” Journal of Epithelial Biology & Pharmacology

7. Crawford C., Wang YH,, Avula B., Clin Toxicol (Phila),  2020 Jan 28 “The scoop on brain health dietary supplement products containing huperzine” A.

8.  Aids Council, June 4, 2015, “Nootropics for improved sexual performance

9. Nicole Prause, Jaymie Park, Shannon Leung and Geoffrey Miller,  PLoS One, 2015, “Women's Preferences for Penis Size: A New Research Method Using Selection among 3D Models

10. Harvard Health Publishing, Harvard Medical School, “5 natural ways to overcome erectile dysfunction

11. Weller, Chris, “Nitric Oxide Beads Beat Out Viagra In Treating Erectile Dysfunction”, in ”Medical Daily”, October, 2015:

12. Gruss, William, “Nobel Prize Discovery Proves You Can Defeat Impotence Now”, in “Natural Health News Report”, May, 2012:

Primal Grow Pro product label

Primal Ultraburst product label

Primal X8 Energy product label