Depending on what you read, melatonin – a common hormone used to help sleep – can cause ED, prevent ED, or treat ED.

Personally, I don’t want to try it, but how about you? Does anyone have ED after taking melatonin?

Anyway, here are some of the reports:

1. Melatonin causes ED:
Cell Mol Neurobiol, 2001 Dec, 21(6):605-16, “Melatonin-dopamine interactions: from basic neurochemistry to a clinical setting”

2. Melatonin prevents ED:
Qiu XF1, Li XX, Chen Y, Lin HC, Yu W, Wang R, Dai YT. Mobilisation of endothelial progenitor cells: one of the possible mechanisms involved in the chronic administration of melatonin preventing erectile dysfunction in diabetic rats. Asian J Androl. 2012 May;14(3):481-6. doi: 10.1038/aja.2011.161. Epub 2012 Feb 27.

Abstract

Diabetes-induced oxidative stress plays a critical role in the mobilisation of endothelial progenitor cells (EPCs) from the bone marrow to the circulation. This study was designed to explore the effects of chronic melatonin administration on the promotion of the mobilisation of EPCs and on the preservation of erectile function in type I diabetic rats. Melatonin was administered to streptozotocin-induced type I diabetic rats. EPCs levels were determined using flow cytometry. Oxidative stress in the bone marrow was indicated by the levels of superoxide dismutase and malondialdehyde. Erectile function was evaluated by measuring the intracavernous pressure during an electrostimulation of the cavernous nerve. The density of the endothelium and the proportions of smooth muscle and collagen in the corpus cavernosum were determined by immunohistochemistry. The administration of melatonin increased the superoxide dismutase level and decreased the malondialdehyde level in the bone marrow. This effect was accompanied by an increased level of circulating EPCs in the diabetic rats. The intracavernous pressure to mean arterial pressure ratio of the rats in the treatment group was significantly greater, compared with diabetic control rats. The histological analysis demonstrated an increase in the endothelial density of the corpus cavernosum after the administration of melatonin. However, melatonin treatment did not change the proportions of smooth muscle and collagen in the corpus cavernosum of diabetic rats. Chronic administration of melatonin has a beneficial effect on preventing erectile dysfunction (ED) in type I diabetic rats. Promoting the mobilisation of EPCs is one of the possible mechanisms involved in the improvement of ED.

  1. Melatonin treats ED: 

Tavukçu HH1, Sener TE, Tinay I, Akbal C, Erşahin M, Cevik O, Cadirci S, Reiter RJ, Sener G.

Melatonin and tadalafil treatment improves erectile dysfunction after spinal cord injury in rats.

Clin Exp Pharmacol Physiol. 2014 Apr;41(4):309-16. doi: 10.1111/1440-1681.12216.

Abstract

Oxidative stress plays an important role both in spinal cord injury (SCI) and erectile dysfunction (ED). The present study investigated the effects of melatonin and tadalafil treatment alone or in combination on SCI-induced ED. Male Wistar albino rats (n = 40) were divided into five groups: sham-operated control and SCI-injured rats given either vehicle, melatonin (10 mg/kg, i.p.), tadalafil (10 mg/kg, p.o.) or a combination of melatonin and tadalafil. Spinal cord injury was induced using a standard weight-drop method. On Day 7 after SCI, intracavernosal pressure (ICP) was measured and all rats were decapitated. Cavernosal tissues were obtained to examine caspase 3, nitric oxide synthase (NOS), myeloperoxidase (MPO) and superoxide dismutase (SOD) activities, as well as cGMP, nerve growth factor (NGF), malondialdehyde (MDA) and glutathione (GSH) levels. Spinal cord injury caused oxidative damage, as evidenced by increases in MDA and cGMP levels. In addition, MPO and caspase 3 activites were increased after SCI, whereas GSH and NGF levels and SOD activity were reduced. Melatonin effectively reversed these oxidative changes. Furthermore, in rats treated with both melatonin and tadalafil, the recoveries were more pronounced than in rats given either melatonin or tadalafil alone. The ICP/mean arterial pressure value in vehicle-treated SCI rats was significantly higher than in the control group, whereas in the tadalafil- and tadalafil + melatonin-treated groups have returned this value had returned to control levels. As an individual treatment, and especially when combined with tadalafil, a well-known agent in the treatment of ED, melatonin prevented SCI-induced oxidative damage to cavernosal tissues and restored ED, most likely due to its anti-oxidant effects.