first off,you never want to use propecia with deca. deca itself converts to dhn,not dht. dhn is a very weak androgen witha very weak affinity to the scalp. using propecia will prevent deca's conversion to dhn,thus causing more hair loss. theoretically,propecia only works with testosterones,not derivatives.
although primobolan is a weak androgen,it does have properties similar to dht as does winstrol,this could explain hairloss from both of these drugs. the are derivatives of dht,not actual dht but similar in structure.
anavar and deca is a safe cycle for hairloss but don't use propecia during this.
Having said all of the above, it should be noted that Primobolan does have some side effects including light acne, deepening voice and increased hair growth. These sides seem to result from the small androgenic component coupled with a very long half life in the system. Remember, the greater the exposure to a compound, the more likely you are to experience side effects. However, it displays low liver toxicity and usually has little effect on blood pressure and cholesterol, which makes it one of the safest injectable anabolic steroids available. It's also worth pointing out that, in men, the body's endogenous testosterone production is only negatively affected when high dosages are taken for prolonged periods of time.