Hi, this is my first post...
I was wondering about this because looking at some of these 'natural' test boosters.... what concerns me is the lack of history regarding the effects of these substances.
It may make one consider at least with the older AS they do have a fairly long track record of use.
Just the fact that you've made the decision to train means your healthier than 70% of the US population that doesn't exercise.
Far as "dangerous" or potentially dangerous supps go. You could say maybe stims if used inappropriately. If you take anything in excess there will be problems. For instance, taking too much calcium can give you kidney stones, headaches and can potentially calcify your arteries. Or Yohimbe products can raise BP too high. Licorice Root extract can cause BP to increase too high as well. Soy products like Isoflavones can effeminize the body and aren't healthy as they are likely GMO soy derived. Some protein products can be produced with trace heavy metals which is why you always pick a quality brand from a GMP facility.
Umm lemmee think of some more....
Caffeine or stims can cause adrenal burnout if overtrained and/or sleep deprived and can give heart problems. Recovery products containing ridiculously high amounts of Dextrose/Malto can make you fat and insulin insensitive. Drinking too much whey too consistently can cause the body to develop a whey allergy where the body sends antibodies to the whey in the gut. Allot of whey comes from corn fed sick cows from a commercial dairy source which cannot likely be good, of course the whey is made from pasteurized cheese which is made from pasteurized milk. Any protein powder in theory is good so long as you get you 3 grams leucine. Say you are a vegan and you drink pea protein, all that means is you need more of the pea protein to get the leucine wheras milk proteins require much less powder to get the same leucine.
Taking too much or any synthetic Vitamin E, Ie- d-alpha-tochopherol-acetate can deplete the levels of other tocopherols/tocotrienols and can be bad for heart and body. Take red palm oil or Toco-8 instead if you want Vitamin E.
Ummm, what else what else..... Some say Milk Thistle can prevent the androgen receptor complex from activating DNA. I've heard of some doctors speak out about taking bolus doses of B-vitamins you see packed in vitamins like animal pak, etc. Creatine EE can elevate creatinine rather high from what I'm told aside from it being proven entirely ineffective compared to CM. Too much sodium in some products can create imbalance in other electrolytes during workouts and dehydrate you. Some sleep GH products now that contain Phenibut have potential for some dependance. Some say there is some neurotoxicity involved with taking D-Asp containing products especially the ones containing some NMDA (ie: muscle warefare NMDA).
What I personally recommend is
-Basic multi from a reputable company.
-antioxidant (grape seed extract, resveratrol/pterosilbene, pynogenol)
-Vitamin C (natural source such as acerola containing bioflavinoids)
-Vit E (natural source Red Palm, Toco8)
-Vit D (5000IU)
-Whey Powder (I buy Native Whey Protein Iso from protein factory, but whatever is good. Change up your brand from time to time) I also sprinkle cinnamon into all my shakes for the insulin effect.
-Creatine Mono (Creapure)
-L-Leucine from Ajinomoto (1-2 grams before meals)
-Digestive Enzymes for those heavy meals
-Preworkout and/or BCAAs for preworkout. I like Hypershock by Myogenix. It's more nutrient based and not crazy on stims. Good amount of BCAAS/Carbs/Arginine/Creatine
-And liquid magnesium (aka magnesium oil) 200-400mg topically pre bed. Most athletes are deficient. Important for muscle recovery, heart health, DHEA levels.
Basic things that work and keep your body running optimal. Save your other money to get a trainer who will guide you and show you how to train with TRUE intensity you may not be training with. And of course save the money for buying real food like eggs, chicken, beef, veges.
Atleast that's how I usually feel, I can't wait to jump on my next cycle of Mass-FX and D-aspartic Acid 
