Related by context. Frequent words. (Click for all words.) 77 oxytocin 62 stress hormones 61 Dopamine 60 Cortisol 60 serotonin 59 dopamine 59 vasopressin 59 endorphins 59 chemical dopamine 59 neurotransmitter dopamine 58 prolactin 58 Serotonin 58 stress hormone cortisol 58 norepinephrine 57 cortisol 56 neurotransmitters 55 endorphin 55 neurotransmitter 55 acetylcholine 54 prostaglandins 54 hormone 53 nitric oxide 53 Hormone 52 Progesterone 52 pheromones 52 progesterone 51 dopamine receptors 51 glutamate 51 neurochemical 51 orexin 50 adenosine 50 chemical messengers 50 GABA 50 hormone estrogen 50 prostaglandin 48 Leptin 48 Melatonin 48 hormones 48 cAMP 48 estradiol 48 theobromine 48 sexual arousal 48 glutamine 48 BDNF 48 secretion 48 Hormones 48 glucocorticoid 47 histamine 47 Hormonal 47 thyroid hormone 47 inflammatory cytokines 47 signaling molecule 47 Sildenafil 46 synthetic hormones 46 neuronal activity 46 aldosterone 46 thyroid hormones 46 naturally occurring protein 46 androgens 46 estrogen 46 glutathione 46 estrogens 46 NPY 46 cytokines 46 male hormone testosterone 46 cortisol levels 46 Nicotine 45 leptin 45 arousal 45 ghrelin 45 adiponectin 45 phenylalanine 45 Naltrexone 45 arginine 45 retinoic acid 44 fatty acid 44 Capsaicin 44 Estrogen 44 Antidepressants 44 dopaminergic 44 nucleus accumbens 44 Testosterone 44 phytoestrogens 44 genistein 44 pain relieving 44 orgasm 44 ovulation 44 pheromone 44 glucocorticoids 44 PYY 43 fatty acids 43 Vitamin B# 43 angiotensin II 43 hormonal 43 inhibitory 43 hypothalamus 43 skeletal muscles 43 salicylic acid 43 gabapentin 43 signaling molecules 43 alkaloids